Plow disk



C.'G. STRANDLUND 2,271,354

' PLOW DISK Filed Feb. 8, 1940 I I INVENTOR: 0ARL 6: STRA/VOL ND.

Patented Jan. 27, 1942 OFFICE PLOW DISK Carl G. Strandlund, Moline,Ill., assignor t Deere & Company, Moline, 111.,

Illinois a corporation of Application February a, 1940, Serial No.317,868

12 Claims.

The present invention relates generally to disk plows and is moreparticularly concerned with plow disks having removable sectionalcutting segments.

The object and general nature of the present invention is the provisionof a plow disk of this character wherein the center'disk section is madeof tough resilient material, such as low carbon semi-soft steel which isrelatively inexpensive, and wherein the cutting edge of the diskcomprises a detachable peripheral section formed of relatively hardwear-resistant material, such as alloy steel, which is relativelyexpensive. the alloy steel peripheral section takes the brunt of thewear while the center disk section possesses the required toughness andstrength to absorb shocks and the like.

A further feature of this invention is the provision of a plow disk inwhich the center disk section is dished and has a substantiallycontinuous concave surface and carries at its peripheral portion adetachable peripheral section, preferably in the form of a plurality ofmating segments, which is also dished and is secured to the center disksection so that the inner surface of the detachable peripheral sectionis substantially a continuation of the concave surface of the centerdisk section. It is quite important, especially in a plow disk, to havethe inner or working face of the disk a smooth and continuous surface,and

it is therefore an additional feature of the present invention toprovide the center disk section with an offset peripheral portion whichhas the required amount of offset to receive the detachable peripheralhardened section so that the inner surface of the latter can becontinuous with the inner surface of the tough and strong center disksection. V

More specifically, it is a further feature of this invention to providea plow disk having a tough center disk section and a detachableperipheral section in the formof a plurality of segments, dished toconform to the curvature of'the center disk section and each having anouter sharpened edge, the corners of which are cut back so as to providenotches. These notches have a two-fold advantage. In the first place,cutting away the outer corners of each segment serves to remove some ofthe material from the segment, especial- 1y the thinner portionsthereof, which is likely to break off in service. Preferably, the amountremoved is sufficient to extend back into the thicker part of thesegment. In the second place, when the segments are assembled, notchesare Thus,

when working in trashy soil. Further, eliminatingthe possibility ofcracking of the segments at the sharpened edge thereof is a specialadvanments, which are formed of hard metal, such as alloy steel, arealso of substantially uniform thickness except, of course, the cuttingedge, which is thinner. Y

These and other objects and advantages of the present invention will beapparent to those skilled in the art after a consideration of thefollowing detailed description, taken in conjunction with theaccompanying drawing illustrating apreferred structure.

In the drawing:

Figure 1 is a face view of a plow disk in which the principles of thepresent invention have been incorporated;

Figure 2 is a sectional view taken at an enlarged scale along the line22 of Figure 1; and

Figure 3 is a fragmentary perspective View of one notched corner, of oneof the peripheral segments.

Referring now to the drawing, the reference numeral I indicates the plowdisk in its entirety, and as shown the plow disk l includes a centerdisk section 2 formed of boiler plate or other material, such as, forexample, tough resilient semiso'ft steel. As best shown in Figure 2, thecenter section 2 is of substantially uniform thickness and includes anoffset section 4, the thickness of wh ch is substantially the same asthe thickness.

of the main body of the center disk 2. 'Ihelatter carries a plurality ofbolts 5, the heads of which are substantially flush with the innersurface ii of the center dis-k section The bolts fi'form a part of thecenter disk section Hand Serve as means whereby the disk may beconnected with a;-suitable supporting bearing structure (not shown) Aswill be clear from Figure'2, the surface 6 of the center disk section isconcave; likewise,-the inner surface 6a of the offset portion 4 lies ina concave surface which is generally'parallel,-or concentric, withrespect to the concave sur- -formed which causev thedisk to operatebetter s; face 6.' The offset part '4 of the central disk 2 is joined tothe main body portion thereof by a curved section I.

The outer peripheral section of the disk I, as indicated by referencenumeral 8, consists of a plurality of segments 9 which, taken together,constitute the peripheral section 8 aforesaid. Each segment 9 is dishedand is formed of bar stock, preferably of alloy steel or otherexceedingly hard wear-resistant material. As best shown in Figure 2,each segment is of substantially uniform thickness and the dishedsurface, indicated at 90, of each segment conforms in concavity to theconcave surface 6. To this end, the amount of offset of the surface 6arelative to the surface 6 corresponds practically exactly to thethickness of the segments 9, whereby the inner surface of the segmentsform a continuationof the concave surface 6. The radially inner edge ofeach segment 9 is beveled, as at I9, to fit snugly and smoothly againstthe curved portion 1 of the center disk section 2. Thus, the entireworking face of the disk I is smooth and continuous, scours easily, andotherwise serves the purpose for which it is intended. Each segment 9 issecured by one or more bolts II to the associated offset 4 of the centerdisk 2. In order to secure and maintain the continuous surface'mentionedabove, the heads of the bolts II are countersunk, as shown in Figure 2.The radially outer edge of each segment 9 is beveled off by plating,preferably in two steps, as shown at I2a (see Figure 3) and I22), thefirst being relatively short and the second extending radially inwardlyto the point I2c. Radially inwardly from this point each segment 9 is ofuniform thickness except for the inner beveled part If]. The beveledpart I2a serves to form a sharpened edge I3, and the edges I3 of thevarious segments 9 form the cutting edge of the disk I.

As best shown in Figures 1 and 3, the radially outer corner of eachsegment 9 is cut away, as at I5. The amount of material removed from thecorners of each segment 9 is not great, but the removed portions extendfrom the sharp cutting edge back through the part of the segment 9 ofrelatively small thickness almost to the point I20 where the segment isof uniform thickness. This is an important advantage of the presentinvention. First, it will be remembered that the segments 9 are formedof hard material, and hence where the peripheral section of the disk isin the form of a plurality of segments with square corners, as shown atI3a (Figure 3) there is some likelihood that the corners of the varioussegments might break off in service, especially since at the corners ofthe sharpened edge I3 the thickness of the segment is small. Accordingto the present invention, I cut off this portion of each segment,bringing the'corner of the segment al- 'most as far back as the pointI20 so as to reach the thicker portions of the segment. The angle a(Figure 3) between the faceof the corner bevel I5 and the cutting edge.-I3 is sufficiently large that there is nomaterial likelihood of thepoint [31) becoming fractured or breaking off. Thus, this constructioneliminates to a large extent the danger of small cracks developing atthe corners of the segment and extending back into the main body of thesegment, and since I thus prevent the small cracks from starting, thesegments of my plow disk are especially long lived.

From Figure 1 it will be seen that the bolts I I fasten the segments 9in position on the offset portion 450 that the edges of the segments 9are in substantial contact, except, of course, at the beveled corners I5where the latter form notches in the cutting edge of the disk. Thesenotches, at I5, have an additional function, other than preventing thesegments from breaking off at the corner and/or cracks developing in thedisks. The notches at I5 cause the disk I to operate better under trashyconditions where ordinary disks tend to slide rather than roll orrotate. The notches at I5 cause the disk to engage the trash, or otherground surface, and to continue rolling, which gives the circularcutting edges I3 a chance to cut through the trash very effectively andcovering it, where ordinary disks would tend to slide and merely pushthe trash ahead.

The number of segments 9 employed may vary as desired, or according tothe number of notches I5 which it is deemed necessary to have. Thesegments 9, being in contact at their edges except for the notches I5,are rigid against backward deflection since, generally speaking, theyserve as an arch. Like the center disk section 2, the segments 9preferably are made by adie forming operation.

While I have shown and described above the preferred constructionembodying the present invention, it is to be understood that myinvention is not to be limited to the specific details shown anddescribed above, but that, in fact, different means may be employed incarrying out the broader aspects of my invention.

What I claim, therefore,.and desire to secure by Letters-Patent is:

l. A plow disk comprising a dished center disk section having an innersubstantially continuous concave surface, a plurality of peripheral wearresisting sections, the inner surface of each of which is dished to forma continuation of the concave surface of said center disk section, and

means connecting said peripheral sections to said center section withthe major part of the ends of said peripheral sections in edge to edgecontact.

2. A plow disk comprising a dished center disk section having aninnersubstantially continuous concave surface and formed of toughsemi-soft steel resistant to-shocks and the like, a'detachableperipheral section formed of hard wear-resistant steel, the innersurface of said detachable peripheral section being 'dished'to form acontinuation of theconcave surface of said center disk section, saidtough center disk section resisting shocks and the like and the hardperipheral section taking the wear during operation, one of saidsectionsbeing offset to receive the adjacent edge of the other sectionand dispose the concave surfaces of the sections substantially flush,and means connecting said sections together.

3. A plow disk comprising a dished center disk section having acontinuous uninterrupted inner concave surface, said center disk sectionhaving an annular offset peripheral portion, a

detachable peripheral section the inner surface of which'is dished toform a continuation of the concave surface of said center disk section,said detachable peripheral section having a radially outer sharpenededge and the thickness of said equal to the thickness of said peripheralsection,

and a plurality of fastening means passing through the radially innerportion of said detachable peripheral section and the adjacent parts ofsaid offset portion of the center disk section for securing saiddetachable peripheral section thereto.

4. A plow disk comprising a dished center disk section formed of toughresilient semi-soft steel and having an inner continuous concave surfaceand a peripheral offset portion, a detachable peripheral sectioncomprising a plurality of separate dished segments, each formed of hardwear resistant metal and having a concavity corresponding to theconcavity of said center disk section, the amount of offset of theperipheral portion of the latter being substantially equal to thethickness of said segments at their radially inner portions thereof,whereby the inner surface of the several segments form a continuation ofthe inner concave surface of said center disk section, each of saidsegments having a sharp-. ened cutting edge and each radially outercorner of each segment being cut off so as to remove a portion of thesharpened cutting edge back to the part of the segment of substantialthickness, the remaining edge portions of the segments being supportedon said peripheral offset portion in substantial contact, and meansfixing said segments to said ofiset portion.

5. A plow disk comprising a center section and a plurality of segmentalsections secured thereto, each of said segments having a sharpenedcutting edge and each radially outer corner of each segment being cutoff so as to remove a portion of the sharpened cutting edge back to thepart of the segment of substantial thickness, thereby forming notches inthe outer periphery of the disk with generally circular cutting edgesections therebetween, whereby the engagement of ground trash and thelike by the notches ensure rolling of the disk in operation and therolling of the disk in operation causing the circular cutting edges tocut through the trash.

6. A plow disk segment comprising a part having a cutting edge, thecorners of said part being out 01f at opposite ends of said cuttingedge.

7. A plow disk segment comprising a part beveled on one side to form acutting edge, the corners of said part at each end of the cutting edgebeing formed on a diagonal which extends at a relatively large angle,greater than 90, to the adjacent portion of the cutting edge.

8. A plow disk comprising a dished center disk section having an innerconcave surface, a detachable peripheral section comprising a pluralityof separate dished segments, each having a concavity corresponding tothe concavity of said center disk section, one of said sections havingan ofiset portion overlapping the back of the other section, the amountof ofiset being substantially equal to the thickness of the adjacentpart of said other section, whereby the inner surfaces of the severalsegments form a continuation of the inner concave surface of said centerdisk section, each of said segments having a sharpened cutting edge.

9. A plow disk comprising a center disk section having an innersubstantially continuous surface, a plurality of peripheral wearresisting sections, the inner surface of each of which is adapted toform a continuation of the inner surface of said center disk section,and means connecting said peripheral sections to said center sectionwith the major part of the ends of said peripheral sections in edge toedge contact.

10. A plow disk comprising a center disk section having a continuousuninterrupted inner surface, said center disk section having an annularofiset peripheral portion, a detachable peripheral section the innersurface of which forms a continuation of the inner surface of saidcenter disk section, said detachable peripheral section having aradially outer sharpened edge and the thickness of said peripheralsection being substantially uniform except at the sharpened edge portionthereof, the amount of offset of said ofiset portion being substantiallyequal to the thickness of said peripheral section, and a plurality offastening means passing through the radially inner portion of saiddetachable peripheral section and the adjacent parts of said offsetportion of the center disk section for securing said detachableperipheral section thereto.

11. A plow disk comprising a dished center disk section formed of toughresilient semi-soft steel, a detachable peripheral section comprising aplurality of separate dished segments, each formed of hard wearresistant metal and having a concavity corresponding to the concavity ofsaid center disk section, each of said segments having a sharpenedcutting edge and each radially outer corner of each segment being cutoff so as to remove a portion of the sharpened cutting edge back to thepart of the segment of substantial thickness, the remaining edgeportions of the segments being supported on said peripheral offsetportion in substantial contact, and means fixing said segments to saidoffset portion.

12. A plow disk comprising a center disk section having an innercontinuous surface and a peripheral offset portion joined together by aslanting section, a detachable peripheral section, the amount of offsetof the peripheral portion of the latter being substantially equal to thethickness of at least the cooperating radially inner portion of thedetachable peripheral section and the radially inner edge of the latterbeing beveled so as to fit said slanting section, whereby the innersurface of the detachable peripheral section forms a continuation of theinner surface of the center section, and means connecting the peripheralsection to said ofiset portion.

CARL G. STRANDLUND.

